參數(shù)資料
型號： MC9S12E256MFU
廠商： MOTOROLA INC
元件分類： 微控制器/微處理器
英文描述： MC9S12E-Family Device User Guide V01.04
中文描述： 16-BIT, FLASH, 25 MHz, MICROCONTROLLER, PQFP80
封裝： QFP-80
文件頁數(shù)： 93/156頁
文件大?。?/td> 3077K
代理商： MC9S12E256MFU
93
4.3 Security
The device will make available a security feature preventing the unauthorized read and write of the
memory contents. This feature allows:
Protection of the contents of FLASH,
Operation in single-chip mode,
Operation from external memory with internal FLASH disabled.
The user must be reminded that part of the security must lie with the user’s code. An extreme example
would be user’s code that dumps the contents of the internal program. This code would defeat the purpose
of security. At the same time the user may also wish to put a back door in the user’s program. An example
of this is the user downloads a key through the SCI which allows access to a programming routine that
updates parameters.
4.3.1 Securing the Microcontroller
Once the user has programmed the FLASH, the part can be secured by programming the security bits
located in the FLASH module. These non-volatile bits will keep the part secured through resetting the part
and through powering down the part.
The security byte resides in a portion of the Flash array.
Check the Flash Block Guide for more details on the security configuration.
4.3.2 Operation of the Secured Microcontroller
4.3.2.1 Normal Single Chip Mode
This will be the most common usage of the secured part. Everything will appear the same as if the part was
not secured with the exception of BDM operation. The BDM operation will be blocked.
4.3.2.2 Executing from External Memory
The user may wish to execute from external space with a secured microcontroller. This is accomplished
by resetting directly into expanded mode. The internal FLASH will be disabled. BDM operations will be
blocked.
4.3.3 Unsecuring the Microcontroller
In order to unsecure the microcontroller, the internal FLASH must be erased. This can be done through an
external program in expanded mode.
Once the user has erased the FLASH, the part can be reset into special single chip mode. This invokes a
program that verifies the erasure of the internal FLASH. Once this program completes, the user can erase
and program the FLASH security bits to the unsecured state. This is generally done through the BDM, but
the user could also change to expanded mode (by writing the mode bits through the BDM) and jumping to
F
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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相關(guān)PDF資料
PDF描述
MC9S12E256MPV MC9S12E-Family Device User Guide V01.04
MC9S12E32 MC9S12E-Family Device User Guide V01.04
MC9S12E32CFU MC9S12E-Family Device User Guide V01.04
MC9S12E32MFU MC9S12E-Family Device User Guide V01.04
MC9S12E64
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC9S12E256MFUE 功能描述:16位微控制器 - MCU MC9S12E256 80 LQFP RoHS:否 制造商:Texas Instruments 核心:RISC 處理器系列:MSP430FR572x 數(shù)據(jù)總線寬度:16 bit 最大時鐘頻率:24 MHz 程序存儲器大小:8 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:VQFN-40 安裝風格:SMD/SMT
MC9S12E256MPVE 功能描述:16位微控制器 - MCU M9S12E256 112LQFP RoHS:否 制造商:Texas Instruments 核心:RISC 處理器系列:MSP430FR572x 數(shù)據(jù)總線寬度:16 bit 最大時鐘頻率:24 MHz 程序存儲器大小:8 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:VQFN-40 安裝風格:SMD/SMT
MC9S12E256VFUE 功能描述:16位微控制器 - MCU MC9S12E256 80-LQFP RoHS:否 制造商:Texas Instruments 核心:RISC 處理器系列:MSP430FR572x 數(shù)據(jù)總線寬度:16 bit 最大時鐘頻率:24 MHz 程序存儲器大小:8 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:VQFN-40 安裝風格:SMD/SMT
MC9S12E256VPVE 功能描述:16位微控制器 - MCU M9S12E256 112LQFP RoHS:否 制造商:Texas Instruments 核心:RISC 處理器系列:MSP430FR572x 數(shù)據(jù)總線寬度:16 bit 最大時鐘頻率:24 MHz 程序存儲器大小:8 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:VQFN-40 安裝風格:SMD/SMT
MC9S12E32CFU 制造商:Rochester Electronics LLC 功能描述:- Bulk
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